The field of the invention is in non-volatile integrated circuit flat film memory. The non-volatility of magnetic memories (retention of data during a power outage) comes about from their rectangular hysteresis loop whereby the memory element retains its magnetization much as in a permanent magnet. Radiation hardness is also a natural consequence of the long-range order in ferromagnetics, which tends not to be disturbed by localized defects generated by radiation exposure. High cyclability is favored by the fact that long term changes in chemical composition due to extreme ambient conditions or to the magnetization process during read and write can be controlled by annealing and passivation.
The planar coupled film memory disclosed here differs from previous inventions in having a symmetrical structure of four magnetic films which provides a flux coupling during both the write and read process, and because its double word line structure, carrying oppositely directed currents, provides maximum noise reduction.